I. Field of the Invention
The present invention relates generally to medical devices for puncturing the skin and more particularly to an acupuncture needle and applicator therefor which provides accurate placement of the needle, ease of insertion, maintains the sterility of the needle before the insertion into the skin, and is readily removable from the placed needle.
II. Description of the Prior Art
Acupuncture has gained increasing acceptance as a medical treatment. The treatment involves the insertion of needles into the skin of a patient at various areas of the body. Typically, the needles are filiform structures, having a length sufficient to permit a portion of the needle to be embedded in the skin to a depth sufficient to produce maximum effect of the treatment and a portion which remains protruded from the skin so that the needle can be removed when the treatment is completed. While these filiform needles can be inserted by skillful hands without additional aid, and can be sterilized to reduce the risk of infection by contamination of the needles, they require extreme care to be protected from contamination before and during their use. Moreover, due to the extremely small diameter and relative long length of these needles, insertion and manipulation of the needles by hand can be difficult. In order to overcome these disadvantages, applicators have been developed which encase the needle and provide a mechanism for releasing the needle from the applicator and inserting it into the skin. One of the previously known types of applicators includes a plunger mechanism for projecting the needle from the enclosure. Such a structure employs numerous parts and is thus quite complicated and expensive to produce.
Another known type of projector applicator is disclosed in U.S. Pat. No. 3,905,375 to Toyama. That patent discloses a needle having an enlarged diameter shank portion which is encased in a pair of tubular members. The ends of the first tube are enclosed by rupturable membranes, and the tube is slidably insertable into the second tube. The second tube has a closed end which abuts against the axial end of the shank of the needle. To discharge the needle, the second tube is depressed over the first tube so as to urge the needle through the rupturable membranes towards the skin of the patient. However, such a device is disadvantageous for the reason that during handling or transportation, the outer tube can be inadvertently depressed over the inner tube, and cause the needle to protrude through the rupturable membrane and become exposed after sterlization. More importantly, since both the needle and the shank of the needle must pass through the membrane in order to remove the applicator from the needle, portions of the membrane may contaminate the site of insertion of the needle. The open end of the shield may not adequately protect the needle from contamination. The ruptured membrane can cause friction between the handle and the shield during the insertion and removal of the shield and plunger assembly, and can possibly pull the needle out of the skin during the process of removal of the assembly.